Equipoised lamp structure



Dec. 28, 1965 J, JACOBSEN ETAL EQUIPOISED LAMP STRUCTURE 2 Sheets-Sheet 1 Filed Dec. 26, 1963 INVENTORS JACOB JACOBSEN JENS C. KROGSRUD ATTORNEYS Dec. 28, 1965 JACOBSEN ETAL 3,226,073

EQUIPOISED LAMP STRUCTURE Filed Dec. 26, 1963 2 Sheets-Sheet 2 D M M U mu w NB f E00 V R w, mM 6 C m 7 B S wN M I 8 H II lvlv b mm is W 2 F M 9 r I: 5 J 7 u O T 8 lm h \1 2 8 9 Jl H li 8 T 1| ATTORNEYS United States Patent 3,226,073 EQUIPOISED LAMP STRUCTURE Jacob Jacobsen and Jens Q. Krogsrud, Oslo, Norway, assignors to Jae. Jacobson AIS, Oslo, Norway, a corporation of Norway Filed Dec. 26, 1963, Ser. No. 333,356 7 Claims. (Cl. 248-280) This invention relates to lamp structures and to the manufacture thereof, and more in particular to lamps of the type which are referred to as equipoised lamps.

An object of this invention is to provide improved lamp structures. Another object is to provide an improved method and apparatus for manufacturing parts and components such as the pivoted arms of equipoised lamps or the like. A further object is to provide structures of the above character which permit great freedom of design and which may be incorporated into various lamp structures. A still further object is to provide for the above with structures which are light in weight, inexpensive to manufacture, and which are efficient, sturdy and dependable in use. These and other objects will be in part obvious and in part pointed out below.

In the drawings:

FIGURE 1 is a perspective view of an equipoised lamp incorporating the invention;

FIGURES 2 and 3 are enlarged views showing details of the lamp of FIGURE 1;

FIGURE 4 is an enlarged sectional view on the line 4-4 of FIGURE 1;

FIGURE 5 is a front view of a punch assembly for fabricating the end structure of the arm which is shown in FIGURE 4;

FIGURE 6 is a perspective view of the elements which are fabricated with the punch assembly of FIGURE 5 to form the arm end structure of FIGURE 4;

FIGURE 7 is a side elevation of the base clamp assembly of FIGURE 1; and,

FIGURE 8 is a view from the left-hand side of FIG- URE 1 showing the base clamp assembly mounted upon a table.

Referring to FIGURE 1 of the drawings, an equipoised lamp 10 has an upper pivoted lever assembly 12, a lamp fixture and shade assembly 38, a lower pivoted lever assembly 14, and a base clamp assembly 16. Pivoted on clamp assembly 16 is a frame unit 26 upon which are pivoted the arms and 17 which form the lower lever assembly 14. The upper end of the lower lever assembly 14 is connected through an intermediate frame unit 32 to the bottom ends of arms 11 and 13 which form the upper lever assembly 12. Arms 11 and 13 are pivoted at their upper ends to a top frame unit 34 upon which is mounted a universal pivot joint assembly 441' to which the lamp fixture and shade assembly 38 is attached.

A pair of springs having telescoping covers 31 is connected between the lower frame unit 26 and the central portion of arms 17, and a pair of similar springs 29 with covers 33 is connected between the intermediate frame unit 32 and the central portion of the arm 13. The lamp arrangement as discussed above is similar to that disclosed in the prior patents of J ac. Jacobson Nos. 2,787,- 434 and 3,041,060, and those patents may be referred to and are incorporated herein for a further understanding of the background of the present invention.

Base clamp assembly 16 is formed by a bracket plate 18 and a clamping screw assembly formed by a bolt 9 threaded into bracket plate 18, a wing nut 5 and a clamp bracket 7 on said bolt. Bracket plate 18 is adapted to rest upon a supporting surface such as the top of a table or desk. Bolt 9 extends down along the edge of the desk and the wing nut 5 is tightened on the bolt 9 so as to urge 3,226,073 Patented Dec. 28, 1965 the clamp bracket 7 against the bottom surface of the desk and firmly hold the base clamp assembly 16 in place. Bracket plate 18 has three screw holes to receive screws by which the bracket plate may be mounted upon only fiat surfaces such as the top of a desk or the like. With such an arrangement, bolt 9, nut 5 and clamp bracket 7 are removed so that the base clamp assembly 16 is the bracket plate 18 and the attaching screws.

Bracket plate 18 has an upright bracket portion 20 which has a central transverse threaded opening, and there is a similarly shaped movable bracket 23 which is clamped to bracket portion 20 by a thumb screw 22 which extends through a central opening in bracket 23 and is threaded into the bracket portion 20 as shown in FIGURE 8. Bracket portion 20 has an annular row of radial ribs 19, or serrations, which are triangular in crosssection and which mate with substantially identical ribs upon bracket 23. Thus, when thumb screw 22 is tightened, the two brackets 20 and 23 are held in fixed relationship. However, when the thumb screw is loosened bracket 23 may be turned with respect to bracket portion 20, thus to change their relative angular position.

Integral with movable bracket 23 is a sleeve 27 which provides a vertical pivot or journal for a pivot 28 of frame unit 26. Frame unit 26 is formed of a single piece of sheet metal so that pivot 28 is a cylinder. Frame unit 26 has two parallel side plate portions 40 which provide the pivots for the lower ends of arms 17 and which also provide the anchors for the lower ends of springs 30. The attachment of each of springs 30 is formed by a loop portion on the end of the spring which is hooked into a somewhat spiral slot 4-2 near the top of the side plate 40, as shown in FIGURE 2. During assembly, the loop end of the spring is hooked into the slot 42 and the tension in the spring is suflicient to insure against detachment.

It has been pointed out above that frame unit 26 provides the pivotal mounting for the lamp, and for proper operation the axis of pivot 28 must be substantially vertical. The base clamp assembly 16 is adapted to provide such a substantially vertical pivotal axis even when the bracket plate 18 is not positioned upon a horizontal surface. Such a circumstance is encountered frequently with lamps of this type, for example, drafting tables the surfaces of which are moved from the horizontal for convenience of working. In such a case the base clamp assembly 16 is attached to the edge of the drafting table and bracket 23 is moved to the position where the axis of its sleeve 27, which holds the pivot 28 of the lower frame unit 26, is vertical. Similarly, bracket portion 18 may be attached to a vertical surface upon a wall or desk or table and the position of bracket 23 is then adjusted appropriately so that the axis of sleeve 27 is substantially vertical.

Referring to FIGURES l and 3, the ends of springs 29 are anchored to arm 13 by a metal bracket 46 which extends through slots 47 in the side walls of the arm and has a central clamping portion 48 which snugly rcceives the arm. The ends of the bracket form hooks 50 in which the looped ends of the springs 29 are positioned. This provides a rigid mounting for the bracket and anchors for the springs; and two or more sets of slots 47 may be provided so that the tension on the springs may be predetermined or changed by the selection of the slot into which the bracket 46 is placed.

Referring now to FIGURE 4 which shows an end of one of the arms 11 (also 13, 15 and 17), a nylon plug 56 is positioned in the end of the arm so as to form a rigid and sturdy end portion. Plug 56 has a peripheral flange 58 which overlies the end of the arm walls, and the exposed portion of the plug provides an attractive and smooth end for the arm. Plug 56 has a transverse bore 60 through which a rivet 62 projects to provide the pivot connection. The arm walls 64 and 66 have openings in alignment with bore 6%, and the walls are flanged 64a 66a into the end of the plug bore 60. This flares the plastic plug 56 under stress and provides a rigid structure so that the plug is held tightly in place and the Wall of bore 60 in the plug provides an antifriction surface with minimum clearance around the rivet 62. Consequently the arm is mounted upon the rivet with minimum play and yet it can swing freely without lubrication. With this construction the arm may be of reduced wall thickness and may be of aluminum. Also, freedom of design is permitted because the pivot may be a rivet or a bolt or another type of shaft.

Referring now to FIGURE 5, there is illustrated the punch assembly of a punch press for producing the reinforced arm end construction of FIGURE 4. A stationary anvil block 68 having a cavity 69 and a transverse bore hole (not shown) is mounted upon a base 70, and there are also guide means (not shown) for the punch press head which carries an inverted U-shaped cam block 72. Block 72 has cam arms 74 and 76 and is mounted to be moved with a fixed reciprocating vertical stroke. Slidably mounted on base 76) is a punch slide '75 which is formed by a pair of punch blocks 78 and 8h positioncd at opposite sides of anvil block 68, and interconnected by upper and lower slide bars 82 and 84, respectively, rigidly fixed thereto. The lower bar 84 forms a guide for the punch slide 75 for limited horizontal movement in the base 70.

Rigidly mounted upon punch block '78 and slidably positioned in the bore hole in the side of anvil block 68 is a relatively sharp nosed punch 86. Punch 86 is adapted to move with its punch block from the position shown to the right so that it projects into cavity 69 of anvil block 68. Similarly mounted upon punch block 80 is a similar punch 88 which is adapted to move toward the left from the position shown so that its leading end projects into cavity 69.

In forming the reinforced end of an arm 11, the plastic plug 56 (see FIGURE 6) is first pushed into the end of the arm. That arm end (see FIGURE is then inserted and held stationary in the cavity 69 of anvil block 68 with the plug being against a stop (not shown) to insure that the arm and plug are in the proper position. Also, care is taken to make certain that the proper side walls of the arm are at the sides of the cavity, i.e., those walls 64 and 66 overlying the bore 60 in the plug 56. In that way the bore 60 in the plug is positioned in exact alignment with the bore holes in the anvil block 68 and with punches 86 and 88. As will be explained below, each stroke of cam block '72 moves punch slide 75 back and forth so as to cause each of punches 86 and 88 to punch a hole in the adjacent side wall of an arm 11 positioned in cavity 69.

The sliding movement of punch slide '75 is produced by inter-engaging cams upon the cam arms 74 and 76 and the respective punch blocks 78 and 80. Cam arm '76 has carn surfaces 90 and 92, and cam arm 74 has cam surfaces 94 and 96; and punch block 80 has cam surfaces 98 and 100, and punch block 78 has cam surfaces 102 and 104. When cam block '72 is in the initial or rest position at the top of its stroke as shown, cam surface 90 of cam arm 76 engages cam surface 98 of punch block 80. At the beginning of a punch stroke of the cam block, the downward movement of cam surface =90 acts through cam surface 98 to move punch slide 75 to the left. This causes punch 88 to pierce through the side wall of the arm 11 which is in cavity 69', and the displaced metal is formed into the flange 66a (see FIGURE 4) at the end of the bore 60 in the plastic plug 56. During this movement punch 86 moves to the left and performs no function.

As block '72 continues to move downwardly, cam surface 90 moves beyond the zone of its engagement with cam surface as, and surface 96 of side cam member 74 moves into engagement with cam surface 102 of punch block 78. This engagement of cam surfaces 96 and 132 moves punch slide to the right so that punch 88 is withdrawn from the hole which it has produced in the arm, and further movement causes punch 86 mounted on punch block 73 to pierce the adjacent side wall of the arm. Punch 86 acts in the same manner as punch 88 so as to produce a hole in the side wall of the arm and to form the displaced metal into a flange 64a which surrounds the adjacent end of the bore 69.

After cam block 72 has reached the end of its stroke, its motion is reversed and it starts to move upwardly, the cam surface 92 of cam arm '76 engages cam surface 1% of punch block so as to move the punch slide 75 to the left again, thus withdrawing punch 86 from its hole and projecting punch 88 back into the hole previously formed by it. The reentry of punch 88 into the previously formed hole corrects any mis-shaping of the flange and hole resulting from the formation of the hole and flange by punch es and insures high-quality workmanship. As block 72 approaches the top of its stroke, cam surface 94 of cam arm 74 engages cam surface 1% of punch block 78 and moves the punch block back to the initial central position wherein both punches are withdrawn from cavity 69. The arm 11 is then removed and the end of another arm is inserted into the cavity, and the operation is repeated.

Lamps constructed in accordance with the present invention are versatile in that they are adaptable for mounting upon various types of desks, tables, and the like and upon other supports whether horizontal or not. Also, the base clamp assembly 16 permits adjustment of the position of the pivot so as to insure that it is vertical. Certain of the improvement features of the illustrative embodiment of the invention may be incorporated into lamp structures without the others and yet the corresponding advantages of the invention are obtained.

As many possible embodiments may be made of the apparatus of the above invention and as the art herein described might be varied in various parts, all without departing from the scope of the invention, it is to be understood that all matter hereinabove set forth, or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.

What is claimed is:

1. In an equipoised lamp mechanism which includes a linkage assembly comprising first and second parallelogram linkages and an intermediate frame unit pivotally interconnecting the linkages in end-to-end relationship and a base frame unit pivotally connected to the other end of one of said linkages and a top frame unit pivotally connected to the other end of the other of said linkages and a lamp unit mounted upon said top frame unit; a pair of spring assemblies one of which is connected at one end to said base frame unit and at the other end to the adjacent parallelogram linkage, the other of said spring assemblies being connected at one end to said intermediate frame unit and at the other end to the other of said parallelogram linkages, each of said spring assemblies comprising a pair of parallel extensible springs, said base frame unit comprising a sheet metal structure including two parallel side plate portions which form the top of the base frame unit and each of which has a slot in its upper end into which the end of one of said springs is connected, the connection between the springs forming the other of said spring assemblies and the other of said parallelogram linkages comprising a bracket having a central portion which snugly engages a linkage arm and two oppositely extending portions to which the respective ends of the springs are hooked, and wherein one of said linkages includes a tubular arm which is substantially square in cross-section and has an end structure formed by a solid plastic plug snugly received in the open end of the arm with a pivot bore therethrough and punched holes in the tube walls in alignment with said pivot bore, and wherein said construction includes a rivet extending through said pivot bore and providing the pivotal connection with said arm end.

2. A lamp mechanism as described in claim 1 wherein each of said punched holes is surrounded by a flange projecting into said plastic plug at the end of said pivot bore.

3. A lamp mechanism as described in claim 2 which includes a base clamp formed by a bracket plate which is adapted to rest upon a supporting surface and a movable bracket portion clamped thereto and adapted to be moved about an axis substantially parallel to the supporting surface, said movable bracket portion providing the pivot bore for said base frame member and removable means attaching said base clamp member to the structure providing said supporting surface.

4. A lamp mechanism as described in claim 3 wherein said removable means comprises a clamping structure formed by means extending transversely through the plane of the supporting surface and means to engage and clamp against an opposed surface parallel to the supporting surface.

5. In a structure of the character described, a tubular arm which has opposite side walls and an open end, a plastic plug snugly positioned within said open end and having fianges overlying the end walls of said arm, said plug having a pivot bore extending between said opposite side walls, each of said side walls having an opening in alignment with said bore and an integral flange portion surrounding the end of the bore and assisting in holding the plug in position, and pivot means in said pivot base.

6. A structure as described in claim 5 wherein said plug is nylon.

7. In an equipoised lamp mechanism which includes a linkage assembly comprising first and second parallelogram linkages and an intermediate frame unit pivotally interconnecting the linkages in end-to-end relationship and a base frame unit pivotally connected to the other end of one of said linkages and a top frame unit pivotally connected to the other end of the other of said linkages and a lamp unit mounted upon said top frame unit; a pair of spring assemblies one of which is connected at one end to said base frame unit and at the other end to the adjacent parallelogram linkage, the other of said spring assemblies being connected at one end to said intermediate unit and at the other end to the other of said parallelogram linkages, each of said spring assemblies comprising a pair of parallel extensible coil springs, said base frame unit comprising a sheet metal structure including two parallel side plate portions which form the top of the base unit and to which the ends of one of said springs is connected, the connection between the springs forming the other of said spring assemblies and the other of said parallelogram linkages comprising a bracket having a central U-shaped portion which is positioned in an opening through a linkage arm with the sides of the U positioned upon the opposite sides of the linkage arm and two oppositely extending portions to which the respective ends of the springs are hooked.

References Cited by the Examiner UNITED STATES PATENTS 887,663 5/1908 Lee 248188.9' 2,076,446 4/ 1937 Carwardine 248-280 2,751,984 6/1956 Kuhl 83-578 2,787,434 4/ 1957 Jacobsen 248280 2,843,205 7/1958 Greulich 83-578 2,891,792 6/1959 Thoeming 272-52 2,926,381 3/1960 De Angelis 16140 3,022,128 2/1962 Reuter 308-238 3,023,059 2/1962 Kirk 308238 CLAUDE A. LE ROY, Primary Examiner.

FRANK L. ABBOTT, Examiner. 

1. IN AN EQUIPOISED LAMP MECHANISM WHICH INCLUDES A LINKAGE ASSEMBLY COMPRISING FIRST AND SECOND PARALLELOGRAM LINKAGES AND AN INTERMEDIATE FRAME UNIT PIVOTALLY INTERCONNECTING THE LINKAGES IN END-TO-END RELATIONSHIP AND A BASE FRAME UNIT PIVOTALLY CONNECTED TO THE OTHER END OF ONE OF SAID LINKAGES AND A TOP FRAME UNIT PIVOTALLY CONNECTED TO THE OTHER END OF THE OTHER OF SAID LINKAGES AND A LAMP UNIT MOUNTED UPON SAID TOP FRAME UNIT; A PAIR OF SPRING ASSEMBLIES ONE OF WHICH IS CONNECTED AT ONE END TO SAID BASE FRAME UNIT AND AT THE OTHER END TO THE ADJACENT PARALLELOGRAM LINKAGE, THE OTHER OF SAID SPRING ASSEMBLIES BEING CONNECTED AT ONE END TO SAID INTERMEDIATE FRAME UNIT AND AT THE OTHER END TO THE OTHER OF SAID PARALLELOGRAM LINKAGES, EACH OF SAID SPRING ASSEMBLIES COMPRISING A PAIR OF PARALLEL EXTENSIBLE SPRINGS, SAID BASE FRAME UNIT COMPRISING A SHEET METAL STRUCTURE INCLUDING TWO PARALLEL SIDE PLATE PORTIONS WHICH FORM THE TOP OF THE BASE FRAME UNIT AND EACH OF WHICH HAS A SLOT IN ITS UPPER END INTO WHICH THE END OF ONE OF SAID SPRINGS IS CONNECTED, THE CONNECTION BETWEEN THE SPRINGS FORMING THE OTHER OF SAID SPRING ASSEMBLIES AND THE OTHER OF SAID PARALLELOGRAM LINKAGES COMPRISING A BRACKET HAVING A CENTRAL PORTION WHICH SNUGLY ENGAGES A LINKAGE ARM AND TWO OPPOSITELY EXTENDING PORTIONS TO WHICH THE RESPECTIVE ENDS OF THE SPRINGS ARE HOOKED, AND WHEREIN ONE OF SAID LINKAGES INCLUDES A TUBULAR ARM WHICH IS SUBSTANTIALLY SQUARE IN CROSS-SECTION AND HAS AN END STRUCTURE FORMED BY A SOLID PLASTIC PLUG SNUGLY RECEIVED IN THE OPEN END OF THE ARM WITH A PIVOT BORE THERETHROUGH AND PUNCHED HOLES IN THE TUBE WALLS IN ALIGNMENT WITH SAID PIVOT BORE, AND WHEREIN SAID CONSTRUCTION INCLUDES A RIVET EXTENDING THROUGH SAID PIVOT BORE AND PROVIDING THE PIVOTAL CONNECTION WITH SAID ARM END. 